Abandonment Procedure for wells on a platform that has fallen over. There are basically two ways to restore control of the wells on a platform that has fallen over. Abandon the wells completely in the order they are accessed, or remove the bent or broken portion of the well and install a subsea wellhead. However, when removing the bent or broken part of the pipe such piping may still be under pressure such pressure dealt with before removal. Otherwise, a blow out could occur.
The present invention relates to the hot tapping multiple coaxial strings of underwater piping and/or tubing for overturned wells and/or platforms.
Under pressure drilling or hot tapping is the process of drilling into a pressured pipe or vessel using special equipment and procedures to ensure that the pressure and fluids are safely contained when access is made. The most common example of a hot tap is into a pressured pipeline. A typical hot tap assembly consists of a saddle assembly with a doughnut-type elastomer pack off, two outboard full-bore flanged valves, a tee assembly and the hot tapping device.
A conventional hot tap device has a polished rod and pack-off assembly which allows movement in the longitudinal direction, as well as rotation while maintaining a seal. A drill bit is installed on the end of the polished rod to drill into the vessel. The means to turn the polished rod may be manual, or by air or hydraulic-generated torque. A threaded sleeve feeds the polish rod assembly and provides the force to resist the pressure area effect that would tend to blow out the polished rod.